APPENDIX. 155 



great help; since filtration after use of alkali is almost impossible, and always most 

 tedious. A. Mr (,'!//. 



< 'oininnit !>// Mr. }\'iitton. Use of paper obviates the slow filtration. 



Page 58, 14. The only exception I take to the method of analysis as outlined is 

 the method of estimating crude fiber. The official method is always tedious, and 

 usually impossible with spices, owing to clogging of Gooch filter. The method as 

 given is liable to be inaccurate, owing to difficulty of transferring fiber from paper, 

 possibility of removing paper fiber, and the assumption that the weight of filter 

 pa PIT after washing with water, alcohol, and ether, and drying at 100 C. is the same 

 as before treatment. A method I have used with satisfaction consists in filtering 

 through linen after acid, and again after alkali treatment, then transferring to Gooch 

 crucible and proceeding as in official method. E. N. Eaton. 



Comment. The method I recommend is that of the A. O. A. C., except that the 

 fiber is weighed on a paper filter instead of the Gooch crucible. I can fully agree 

 with Eaton that the "official method is always tedious and usually impossible 

 with spices, owing to the clogging of Gooch filter/' but I prefer a paper, both for the 

 acid and alkali filtration. There is little danger of fiber being detached from the 

 paper after the acid filtration. 



Page 59, 16. I think the Jena flasks used in determining nitrogen of nonvolatile 

 ether extract should be described more exactly, whether round or flat-bottomed, 

 length of neck, etc. Would it not be satisfactory to make extraction in the ordinary 

 flask and transfer with water or ether? The ilask you prescribe could not be used 

 with the Knoor extraction apparatus. W. 1). Bi<j<'l<>n-. 



Comment by Mr. Winton. I prefer a flat-bottomed Jena flask, 15 centimeters high, 

 but other shapes and sizes may be used without affecting the result. The extract, 

 after drying, is not easily removed with ether; hence it is strongly advised to digest 

 for nitrogon in the extraction flask, transferring to a larger flask for distillation. 

 The kind of apparatus used is not important, provided the extraction and digestion 

 are complete, and mechanical loss is avoided. 



FLAVORING EXTRACTS. 



Page 70, 4. I would suggest the following method for the estimation of vanillin:* 

 Two cubic centimeters of the vanilla extract, is measured into a test tube and sufficient 

 freshly precipitated lead hydroxid added to completely decolorize. The mixture is 

 washed onto a filter and the filtrate and washings collected in a Nessler tube. Bro- 

 min water is then added, after which enough of a freshly prepared 10 per cent solu- 

 tion of ferrous sulphate is added to get the maximum bluish-green color that will be 

 produced if vanillin is present. 



A standard solution is prepared by dissolving, say 50 mm of pure vanillin in 100 cc 

 of water. A series of standards is then made, taking for instance , 1, 2, 2$, 3, etc., 

 cc of the vanillin solution in Nessler tubes, each being treated with 2 or 3 drops of 

 Bromin water, and with ferrous sulphate solution, and made up to the 50-cc mark. 



The lead hydroxid is prepared by dissolving 200 grams of lead acetate in 850 cc of 

 water. The solution is filtered and a strong solution of potassium hydroxid is added 

 in excess, and the precipitate is washed thoroughly several times by decantation. b 

 A. E. Leach. 



FERMENTED AND DISTILLED LIQUORS. 



Page 83, 6. When a liquor is titrated and the indicator does not give the color 

 reaction distinctly on account of the color of the liquor after that point where the 

 red goes to violet, the end reaction is gotten by dipping a capillary tube into the 



Ztschr. anal. Cheni., 189-1, tf:$, urj. 



bZtschr. anal. Cheni., 1894, 38, 241>; -Mass. Hoard of Ili-.-ilih Jlt-pt. tor js-i-.i. r,-.".i. 



